Transfer failed while external call in through SIPT

[osw200051]

Hi All,

I am facing the issue and do not know how to fix.

Situation:

External phone call -> ISP SIPT->CUBE->CUCM->IP Phone A

When IP Phone A click transfer button to IP Phone B, external phone be hold. When IP Phone A click transfer button again to transfer the call, external phone is disconnected.

I have no idea about the issue.

Could anyone have some idea and help me to fix it?

Thanks 

[Manish Gogna]

It could likely be an issue with MTP or transcoder allocation failure during the transfer. Please check if Media termination Point Required is checked on SIP trunk and if correct MTP / transcoding resources are present in the MRGL. If you make any changes then reset the SIP trunk and test again. If the issue persists then post the detailed callmanager service traces so that the SIP signaling and media resource allocation can be checked.

Manish

[osw200051]

Hi all,

Well noted your point.

On the SIP trunk, I had already add the media resource on MTP.

But I am no sure whether I need to check the "Media Termination Point Required" checkbox in CUCM SIP Trunk configuration or not.

Thanks 

[Manish Gogna]

You can go to the SIP profile applied on the SIP trunk and set the "Early Offer support for voice and video calls" parameter to Mandatory (insert MTP if needed). With this setting Unified CM inserts a media termination point (MTP) if the media characteristics of the calling device cannot be determined (for example, for an inbound Delayed Offer call forwarded over an Early Offer SIP trunk).

Manish

[Mohammed Khan]

Worth checking Cisco Call manager logs, if you have collect can you share it here.

Regards,

Mohammed Noor

[osw200051]

Hi Khan,

I think I need to do it. 

Would share what debug command you recommend?

In normal, I would use debug voice ccapi inout.

[Mohammed Khan]

Collect below debug

++ debug ccsip messages

++ debug voice ccapi inout

From CUCM RTMT, Collect Cisco Callmanager Logs

Regards,

Mohammed Noor

[Suresh Hudda]

Seems media resource unavailability issue...try to check MTP on sip trunk (CUCM-CUBE) and make sure mrgl with mtp resources is assigned to sip trunk as well.

Suresh

[Mohammed al Baqari]

In CUBE try this command

voice service voip

no suppl sip refer

no suppl sip move

MTP is usually needed for H323 transfers but not for SIP. Try to fix it without MTP (unless you are using different codecs between call legs)

[osw200051]

Thanks all,

Problem solved after adding MTP on the trunk.

Thanks

[ozden ozdugun]

Hi;

ı have the same problem not transfer outbound the inbound .where do you add the mtp ?

Thanks